The abuse and misuse of opioids has led to an epidemic of major proportions that has impacted all sociodemographic groups in the USA and led to an unfathomable number of deaths each year. Of the millions of people suffering today from an opioid use disorder, the normal treatments are opioid agonist medication therapies that have marked stigma and are subject to restrict governmental regulations that unfortunately have limited the number of people possible to treat. Moreover, although such opioid treatment strategies have improved substance use outcomes, they do not effectively treat opioid craving that might result in high rates of relapse. Using a strategy of indirectly regulating neural systems to modulate opioid-related behavior, our preclinical rodent studies had previously demonstrated that cannabidiol (CBD), a non-rewarding component of cannabis, specifically inhibited cue-induced heroin-seeking behavior. CBD's selective effect on drug-seeking behavior endured two or more weeks after the last drug administration following short-term CBD exposure. Intriguingly, these effects were replicated in a randomized double-blinded human study where abstinent heroin abusers reported reduced cue-induced drug craving (and anxiety) following acute CBD administration and the effects persisted even a week after the last administration of the CBD. The fact that drug craving is generally triggered by exposure to conditioned cues suggests that CBD might be an effective treatment for heroin craving and related behaviors that maintain the chronic relapsing nature of this disorder. CBD thus represents a strong candidate for the development as a potential therapeutic agent in humans for opioid craving and relapse prevention. However, the neurobiological effects of CBD are still unknown. It is the goal of this translational project to (1) Characterize the effects of CBD on neural connectivity and cue-induced neural activity within mesocorticolimbic brain circuits in abstinent heroin subjects using systems-level functional magnetic resonance imaging (fMRI), (2) Determine CBD effects on in vivo glutamatergic (and related neurometabolites) using Proton-Magnetic resonance spectroscopy (1H MRS) and (3) Elucidate glutamatergic and related synaptic plasticity mechanisms underlying the effects of CBD on heroin seeking behavior in translational rodent models using MRS, in vivo photometry (neural activity) and molecular and epigenetic sequencing of discrete brain regions. Altogether, knowledge obtained from this unique translational study will advance fundamental understanding of the neurobiology underlying phenotypes that drive addiction and provide science-based evidence towards the development of CBD as a new therapeutic tool to help address the opioid crisis.